Applying a decision-making framework for resolving conflicts when selecting windows and blinds

Figures & data

Figure 1. Section and plan layout of the office room.

Table 1. Thermal specifications for the office room.

Building envelope	U-value
External walls	0.4 (W/m^2. K)
Internal walls	0.6 (W/m^2. K)
Windows	1.2 (W/m^2. K)
Roof	0.16 (W/m^2. K)

Figure 2. the decision-making framework (Jalilzadehazhari et al., 2018).

Table 2. Various properties of the windows

Window	Properties
3-pane window type 1 (Elitfonster, 2016)	U-value = 1.2 (W/m^2. K) VT* = 72% SHGC** = 50%
3-pane window Type 2 (Elitfonster, 2016)	U-value = 1.1 (W/m^2. K) VT* = 70% SHGC** = 49%
3-pane window Type 3 (Elitfonster, 2016)	U-value = 1 (W/m^2. K) VT* = 66% SHGC** = 48%
3-pane window Type 4 (Elitfonster, 2016)	U-value = 0.9 (W/m^2. K) VT* = 65% SHGC** = 45%
3-pane window Type 5 (Elitfonster, 2016)	U-value = 0.8 (W/m^2. K) VT* = 63% SHGC** = 43%
Electrochromic window type 6 (Sbar, Podbelski, Yang, & Pease, 2012)	U-value = 1.3 (W/m^2. K) VT* = 62% clear SHGC** = 0.47% clear VT* = 21% intermediate SHGC** = 17% intermediate VT* = 2% fully tinted SHGC** = 9% fully tinted

*VT: visual transmittance.

**SHGC: Solar heat gain coefficient.

Table 3. The properties of the internal and external blinds.

Blinds	Properties
	Internal venetian blind (Elitfonster, 2016)
	• Visible transmittance of louvres	0%
	• Louvre thickness	0.001 (m)
	• Louvre width	0.02 (m)
	• Blind-to-glass distance	0.1 (m)
	Internal roller curtain (Elitfonster, 2016)
	• Visible transmittance*	0%
	• Curtain conductivity	0.1
	• Openness of the curtain	3%
	• Blind-to-glass distance	0.1 (m)
	* Fabric treated as an opaque material
	External venetian blind (Warema, 2018)
	• Visible transmittance of louvres	0%
	• Louvre thickness	0.001 (m)
	• Louvre width	0.080 (m)
	• Blind-to-glass distance	0.1 (m)
	External overhang panel (Warema, 2018)
	• Visible transmittance*	0%
	• Panel installation height above window	0.265 (m)
	• Panel-to-glass distance in fully closed condition	0.090 (m)
	• Left and right extensions from window	0.1 (m)
	* Fabric treated as an opaque material

Figure 3. The position of lighting zones and two reference points.

Table 4. Cost per unit for windows and blinds.

Design variables	Investment cost (SEK/m^2)
Windows
Type 1 (Elitfonster, 2016)	2870
Type 2 (Elitfonster, 2016)	3310
Type 3 (Elitfonster, 2016)	4000
Type 4 (Elitfonster, 2016)	4430
Type 5 (Elitfonster, 2016)	4770
Type 6 (SageGlass, 2018)	25000
Internal venetian blind (Elitfonster, 2016)	845
Internal roller curtain (Elitfonster, 2016)	1305
External venetian blind (Warema, 2018)	4500
External overhang panel (Warema, 2018)	11800

Figure 4. A 3D layout of an office room.

Table 5. Codification settings.

Window and blind design variables	Lower boundary	Upper boundary	Interval
Size, position and form of window on south façade
${\mathrm{X}}_{\mathrm{a}}={\mathrm{X}}_b$	${\mathrm{X}}_{\mathrm{A}}-0.5$ (m)	${\mathrm{X}}_A-0.05$ (m)	0.05 (m)
${\mathrm{X}}_{\mathrm{c}}={\mathrm{X}}_d$	${\mathrm{X}}_{\mathrm{D}}+0.05$ (m)	${\mathrm{X}}_{\mathrm{D}}+0.5$ (m)	0.05 (m)
$Z_a={\mathrm{Z}}_d$	$Z_D+0.05$ (m)	${\mathrm{Z}}_D+0.5$ (m)	0.05 (m)
$Z_b={\mathrm{Z}}_c$	$Z_C-0.5$ (m)	${\mathrm{Z}}_C-0.05$ (m)	0.05 (m)
Size, position and form of window on west façade
${\mathrm{Y}}_e=Y_f$	${\mathrm{Y}}_D+0.05$ (m)	${\mathrm{Y}}_D+0.5$ (m)	0.05 (m)
$Y_g=Y_h$	$Y_E-0.5$ (m)	$Y_E-0.05$ (m)	0.05 (m)
$Z_e={\mathrm{Z}}_h$	$Z_D+0.05$ (m)	${\mathrm{Z}}_D+0.5$ (m)	0.05 (m)
$Z_f={\mathrm{Z}}_g$	$Z_C-0.5$ (m)	${\mathrm{Z}}_C-0.05$ (m)	0.05 (m)
Window type	1	6	1
Internal venetian blind
Slope angle of louvres	10°	90°	10°
Visible reflectance of louvres	20%	80%	20%
Internal roller curtain
Visible reflectance of curtain	10%	70%	20%
External venetian blind
Slope angle of louvres	10°	90°	10°
Visible reflectance of louvres	20%	80%	20%
External overhang blind
Panel's width as a fraction of the window height	0.5	1	0.1
Tilt of the panel	10°	90°	10°

Figure 5. The hierarchy model developed for the AHP.

Table 6. Pairwise numerical rating (Saaty, 2008).

AHP, relative importance		Numerical rating
Equal importance	Two factors contribute equally to the objective	1
Slightly more important	Experience and judgment slightly favour one over the other	3
More important	Experience and judgment strongly favour one over the other	5
Much more important	Experience and judgment very strongly favour one over the other. Importance is demonstrated in practice	7
Definitely more important	Evidence favouring one over the other is of the highest possible validity	9
Intermediate values	When compromise is needed	2, 4, 6, 8

Table

A =		$\begin{array}{cccc}\mathrm{V}\mathrm{i}\mathrm{s}\mathrm{u}\mathrm{a}\mathrm{l}& \mathrm{T}\mathrm{h}\mathrm{e}\mathrm{r}\mathrm{m}\mathrm{a}\mathrm{l}& \mathrm{E}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y}& \mathrm{L}\mathrm{i}\mathrm{f}\mathrm{e}\mathrm{c}\mathrm{y}\mathrm{c}\mathrm{l}\mathrm{e}\\ \mathrm{c}\mathrm{o}\mathrm{m}\mathrm{f}\mathrm{o}\mathrm{r}\mathrm{t}& \mathrm{c}\mathrm{o}\mathrm{m}\mathrm{f}\mathrm{o}\mathrm{r}\mathrm{t}& \mathrm{c}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{u}\mathrm{m}\mathrm{p}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}& \mathrm{c}\mathrm{o}\mathrm{s}\mathrm{t}\end{array}$	Weight
	Visual comfort	$\left[\begin{array}{ccccccccccccc}1& & & 2& & & & 7& & & & & 7\\ 1/2& & & 1& & & & 7& & & & & 7\\ 1/7& & & 1/7& & & & 1& & & & & 1\\ 1/7& & & 1/7& & & & 1& & & & & 1\end{array}\right]$	0.52
	Thermal comfort		0.36
	Energy consumption		0.06
	Life cycle cost		0.06

Table 7. Random consistency index (RI).

n	1	2	3	4	5	6	7	8	9	10
RI	0	0	0.58	0.9	1.12	1.24	1.32	1.41	1.45	1.49

Table

B =		$\begin{array}{ccc}{\mathrm{H}}_{\mathrm{i}\mathrm{l}\mathrm{l}>500}& {\mathrm{H}}_{\mathrm{D}\mathrm{G}\mathrm{I}>22}& \mathrm{U}\end{array}$	Weight
	${\mathrm{H}}_{\mathrm{i}\mathrm{l}\mathrm{l}>500}$	$\left[\begin{array}{ccc}1& 2& 3\\ 1/2& 1& 2\\ 1/3& 1/2& 1\end{array}\right]$	0.54
	${\mathrm{H}}_{\mathrm{D}\mathrm{G}\mathrm{I}>22}$		0.3
	U		0.16

Table 8. Final weight of the criteria.

Criteria	Final weight
${\mathrm{H}}_{\mathrm{i}\mathrm{l}\mathrm{l}>500}$	0.52 × 0.54 = 0.28
${\mathrm{H}}_{\mathrm{D}\mathrm{G}\mathrm{I}>22}$	0.52 × 0.3 = 0.156
U	0.52 × 0.16 = 0.08
PMV	0.36
${\mathrm{E}}_{\mathrm{t}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l}}$	0.06
${\mathrm{K}}_{\mathrm{n}}$	0.06

Figure 6. Amount of daylight and glare among window and blind designs.

Figure 7. Uniformity among window and blind designs.

Figure 8. PMV among window and blind designs.

Figure 9. Energy consumption and present value among window and blind designs.

Table 9. Window and external venetian blind specifications in a trade-off design.

Design variables
Window type	1
Window on south façade 33
$X_a=X_b$	$X_A-0.25$
$X_c=X_d$	$X_D+0.40$
$Z_a=Z_d$	$Z_D+0.50$
$Z_b=Z_c$	$Z_C-0.05$
Window on west façade
$Y_e=Y_f$	$Y_D+0.05$
$Y_g=Y_h$	$Y_E-0.10$
$Z_e=Z_h$	$Z_D+0.50$
$Z_f=Z_g$	$Z_C-0.05$
Slope angle of louvres	60
Visible reflectance of louvres	80%

Jalilzadehazhari, E., Johansson, P., Johansson, J., & Mahapatra, K. (2018). Developing a decision-making framework for resolving conflicts when selecting windows and blinds. Architectural Engineering and Design Management. doi: 10.1080/17452007.2018.1537235

 Google Scholar

Elitfonster. (2016). Retrieved from www.elitfonster.se

 Google Scholar

Sbar, N. L., Podbelski, L., Yang, H. M., & Pease, B. (2012). Electrochromic dynamic windows for office buildings. International Journal of Sustainable Built Environment, 1(1), 125–139. doi: 10.1016/j.ijsbe.2012.09.001

 Google Scholar

Warema. (2018). Retrieved from https://www.warema.com/en/

 Google Scholar

SageGlass. (2018). Retrieved from https://www.sageglass.com/en

 Google Scholar

Saaty, T. L. (2008). Decision making with the analytic hierarchy process. International Journal of Services Sciences, 1(1), 83–98. doi: 10.1504/IJSSCI.2008.017590

 Google Scholar